If you run with a competent zNec and don't punch above your DPS' weight GR tier wise, everything will be frozen/get murdered as you go, and rat deaths become very infrequent in a play session, so the choice becomes a question of preference. I run with SLW because even though I am mobile for 90% of a GR, with SLW I can move freely and play relaxed, because I don't have that low level anxiety that I cannot stop that I get with Hexing Pants, which demand almost constant split-second decision making and therefore lead to more errors in judgment -- poor placement.

Remember that ratruns are all about balance and momentum, and your zNec's ability to perma-freeze is contingent on how fast the DPS kill things. So if there is frequent unforced downtime on your zNec's LoTD (which can happen naturally with empty-ish maps, a particularly nasty jugg or a far spawning boss), then it's usually a sign that your DPS need to go down a few GR tiers to find that rat DPS : zNec CDR equilibrium. Deaths become quite rare with a good team playing in that sweet spot, in my experience.